B757 crew had multiple near midair collision and TCASII RA in ord class B airspace.

Attributes
ACN	444425
Time
Date	199907
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : ord.airport
State Reference	IL
Altitude	msl single value : 2000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : ord.tower
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 27l other
Flight Phase	descent : approach
Route In Use	approach : visual approach : instrument precision
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tower : ord.tower
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : flight engineer pilot : commercial pilot : cfi pilot : atp pilot : multi engine
Experience	flight time last 90 days : 90 flight time total : 5500 flight time type : 1200
ASRS Report	444425
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 250 flight time total : 11000 flight time type : 500
ASRS Report	444423
Events
Anomaly	conflict : nmac non adherence : required legal separation non adherence : published procedure non adherence : far
Independent Detector	aircraft equipment : tcas
Resolutory Action	flight crew : executed go around flight crew : took evasive action
Miss Distance	horizontal : 200 vertical : 0
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

We were on an ILS approach to runway 27L at ord in VMC. At the marker (6.1 DME) we switched to tower frequency, but were unable to check in due to frequency congestion. At approximately 2000 ft MSL we got a TCASII TA and about 2-3 seconds later we got a TCASII RA with a command to climb. We immediately followed the RA commands. The target showed an altitude of 2000 ft and about 1 O'clock. The tower then contacted us by asking if we were on frequency. (We were leveling off from the TCASII commanded climb because the RA had stopped.) tower told us to execute a missed approach and assumed an immediate left turn and climb. At that time we got a second RA with another command to climb. We made another climb, followed the tower instructions, and were handed off for another uneventful approach and landing. A pilot seated in the cabin estimated that we were 200-300 ft horizontally from a light aircraft, same altitude.

Original NASA ASRS Text

Title: B757 CREW HAD MULTIPLE NMAC AND TCASII RA IN ORD CLASS B AIRSPACE.

Narrative: WE WERE ON AN ILS APCH TO RWY 27L AT ORD IN VMC. AT THE MARKER (6.1 DME) WE SWITCHED TO TWR FREQ, BUT WERE UNABLE TO CHK IN DUE TO FREQ CONGESTION. AT APPROX 2000 FT MSL WE GOT A TCASII TA AND ABOUT 2-3 SECONDS LATER WE GOT A TCASII RA WITH A COMMAND TO CLB. WE IMMEDIATELY FOLLOWED THE RA COMMANDS. THE TARGET SHOWED AN ALT OF 2000 FT AND ABOUT 1 O'CLOCK. THE TWR THEN CONTACTED US BY ASKING IF WE WERE ON FREQ. (WE WERE LEVELING OFF FROM THE TCASII COMMANDED CLB BECAUSE THE RA HAD STOPPED.) TWR TOLD US TO EXECUTE A MISSED APCH AND ASSUMED AN IMMEDIATE L TURN AND CLB. AT THAT TIME WE GOT A SECOND RA WITH ANOTHER COMMAND TO CLB. WE MADE ANOTHER CLB, FOLLOWED THE TWR INSTRUCTIONS, AND WERE HANDED OFF FOR ANOTHER UNEVENTFUL APCH AND LNDG. A PLT SEATED IN THE CABIN ESTIMATED THAT WE WERE 200-300 FT HORIZLY FROM A LIGHT ACFT, SAME ALT.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.